PURPOSE: To improve workability by providing the rotational center of a turning table supporting a boom or a link arm device, and to be turned above a vehicle body so that it may be optionally moved between the car width directional center of the vehicle body and the eccentric position.

CONSTITUTION: One end of a swing arm 12 is supported on a supporting strand 10 installed on the center part in the width direction of a load carrying platform 2 through a turning bearing 11 so as to be turned, and it is driven by a hydraulic motor attached inside the swing arm l2. A turning table 3 is supported on the other end of the swing arm 12 through the turning bearing so as to be turned, and the lower end of a link arm device 4 is supported to the turning table 3. By this structure, the swing arm 12 is swung in wiring work as needed, and the turning center of the turning table 3 is made eccentric from the center part in the width direction of the load carrying platform 2. Since the movement of the link arm device 4 is not restricted by an overhead wire, the overhead wire is not damaged, and the working range from a packet 5 can be widely taken.